Biological fouling is a major limitation in many applications, including food and biotechnology processing, marine structures such as ship hulls and oil rigs, surgical instruments, and wastewater treatment. Biological fouling (adhesion of interacting retained solutes like proteins, viruses, DNA, and cells) and concentration polarization (build-up of non-interacting retained solutes like ions near the surface) ultimately lead to a decrease in performance and an increase in energy use.
Ultrafiltration membranes are widely used in the biotechnology, food, beverage, and water industries. A major source of fouling is non-specific protein binding to the membrane surface. As upstream feed titers increase, especially in the biotechnology industry, the majority of the operating costs of the entire process are shifted heavily to the downstream processes.
For over 40 years, both interfacial polymerization and phase inversion have been the predominant methods for preparing asymmetric and composite polymeric membrane structures. Although these synthesis methods have been very successful, they are relatively complex, sensitive to small changes in the casting conditions, susceptible to residual chlorine, and produce rough membrane surfaces that enhance membrane fouling. Many research groups have sought novel synthesis methods for producing improved polymeric synthetic membranes without much success. Such membranes have too low a porosity (track etched), are too expensive (ceramic or stainless steel), possess too wide a pore size distribution (stretched PTFE), or too fragile (biological).
Thus, new high performance low-fouling synthetic membranes are needed. A facile, fast, and inexpensive method to assist in the discovery of new low fouling coatings is also urgently needed.